Gibbs Sampling for (Coupled) Infinite Mixture Models in the Stick Breaking Representation

Nonparametric Bayesian approaches to clustering, information retrieval, language modeling and object recognition have recently shown great promise as a new paradigm for unsupervised data analysis. Most contributions have focused on the Dirichlet process mixture models or extensions thereof for which efficient Gibbs samplers exist. In this paper we explore Gibbs samplers for infinite complexity mixture models in the stick breaking representation. The advantage of this representation is improved modeling flexibility. For instance, one can design the prior distribution over cluster sizes or couple multiple infinite mixture models (e.g. over time) at the level of their parameters (i.e. the dependent Dirichlet process model). However, Gibbs samplers for infinite mixture models (as recently introduced in the statistics literature) seem to mix poorly over cluster labels. Among others issues, this can have the adverse effect that labels for the same cluster in coupled mixture models are mixed up. We introduce additional moves in these samplers to improve mixing over cluster labels and to bring clusters into correspondence. An application to modeling of storm trajectories is used to illustrate these ideas.Comment: Appears in Proceedings of the Twenty-Second Conference on Uncertainty in Artificial Intelligence (UAI2006

From gatekeepers to gateway constructors: Credit rating agencies and the financialisation of housing associations

This paper uses the twin metaphors of ‘gatekeeper’ and ‘gateway constructor’ as devices to explore the role of Credit Rating Agencies (CRAs) as intermediaries between global corporate finance and specific institutions – housing associations in England. The analysis utilises a financialisation framing, whereby the practices, logics and measurements of finance capital, increasingly permeate government, institutional and household behaviour and discourse. This paper examines how housing associations have increasingly resorted to corporate bond finance, partly in response to reductions in government funding, and in the process engaged with CRAs. Surprisingly little research has been undertaken on the role and function of CRAs, and their impact on the organisations they rate. The case of housing associations (HAs) is of particular interest, given their historical social mission to build and manage properties to meet housing need, rather than operate as commercial private landlords conversant with market-based rationales. A case study of the large London-based HAs draws on a narrative and financial analysis of annual reports, supplemented by semi-structured interviews with senior HA finance officers to explore how CRA methodologies have been internalised and have contributed to changes in strategic and operational activities. We conclude that CRAs act both as a gatekeeper to the financial markets but also as a gateway constructor for the financial markets to enter new arenas, such as the HA sector. This dual nature of CRAs is intended as our contribution to emerging debates about the nature, the practice and the impact of financialisation on public services

Neighbourhood identity

From Executive Summary: This study explores the ways in which neighbourhood identity is formed over time and place, and considers the implications this may have for policies that seek to improve and enhance neighbourhoods and communities. Part of the motivation for the study was to explore why ‘regeneration policies’ often fail in their objectives and why the reputations of housing estates – ‘good’ and ‘bad’ – display a remarkable longevity and resilience to change. Hence the interest focused on how such reputations are established and understood by those within and outside of particular places, and what implications this has for the identities of neighbourhoods and the individuals who live in them. In so doing, the study concentrated on three neighbourhoods in the City of Stirling in central Scotland, namely, Raploch, Riverside and Randolph Road. Each was chosen for its distinct socio-economic profile and differing relative identity. To this end, the study also explored what it meant to individuals to ‘come fae’ (come from) each of these areas as a way of understanding issues of ‘belonging’ and ‘attachment’ to particular places

Using the Delphi Technique to Determine Which Outcomes to Measure in Clinical Trials: Recommendations for the Future Based on a Systematic Review of Existing Studies

Ian Sinha and colleagues advise that when using the Delphi process to develop core outcome sets for clinical trials, patients and clinicians be involved, researchers and facilitators avoid imposing their views on participants, and attrition of participants be minimized

Laboratory apparatus for in-situ corrosion fatigue testing and characterisation of fatigue cracks using X-ray micro-computed tomography

This paper presents the design, construction, and assembly of laboratory apparatus to undertake in‐situ corrosion fatigue tests in a sour corrosive environment under uniaxial fatigue loading. The bespoke test cell allows periodic nondestructive X‐ray micro‐computed tomography of the specimen in‐situ during fatigue testing and thus enables monitoring of material degradation in‐situ as it progresses and in particular the pit‐to‐crack transition. This approach provides more direct information on crack initiation than complementary ex‐situ techniques such as scanning electron microscopy of post‐test metallographic specimens. Moreover, the apparatus was designed to allow a fatigue cycle to be interrupted and maintain the sample under static tensile load, during X‐ray tomography scans. This process reduced the risk of premature crack closure during interrupted tests. Results presented herein demonstrate the performance and reliability of our approach and will hopefully stimulate other groups to use similar “lab‐scale” initiatives

“The sweetest songs” - Ethical framing in fundraising throughthe agency of service users/contributors to tell their ownstories

Much of the discussion on the ethics of the framing of service users in fundraising and marketing materials focuses on the ethical dilemma of whether the means of using negative framing and negatively-framed images—which it is argued are more effective at raising money—justify that end if they cause harm by stereotyping and “othering” the people so framed, rob them of their dignity, and fail to engage people in long-term solutions. Attempts to find the right balance between these two ethical poles have proved elusive. This paper posits a new ethical solution by removing these two poles from the equation and making the ethicality of fundraising frames contingent on the voice and agency of service users/contributors to tell their own stories and contribute to their own framing: as the Niger proverb says, “a song sounds sweeter from the author's mouth.

Energetische Bewertung der Bereitstellung ausgewählter lokaler Lebensmittel am Beispiel dreier Fleischarten

In der vorliegenden Studie erfolgt eine energetische Bewertung der Bereitstellung dreier Fleischarten als Beispiel für lokale Lebensmittel. Anwendung findet eine modifizierte Form zur Berechnung des Kumulierten Energieaufwandes (KEA). Zu diesem Zweck erfolgt die Untersuchung lokaler Bereitstellungsprozesse für Schweinefleisch, Rindfleisch und Lammfleisch sowie ungarischer Bereitstellungs-prozesse für Schweinefleisch (in Ungarn regional bereitgestellt) mittels standardisierter Fragebögen hinsichtlich der Produktions- und Vermarktungsabläufe. Darüber hinaus findet eine vergleichende Bewertung einer Prozesskette für argentinisches Rindfleisch statt. Anhand der Module Transport, Mast-Elektroenergie, Mast- s.E. (sonstige Energie), Schlachtung/Zerlegung sowie Distribution findet die Ergebnisdarstellung mittels Allokation auf die funktionelle Einheit von 1 kg Fleisch ohne Knochen statt. Nach Auswertung aller energierelevanten Daten ergibt sich die Feststellung, dass die Umsätze an Endenergie und Primärenergie sowie die CO2-Emissionen mit steigender Betriebsgröße abnehmen. Die Verbrauchereinschätzung, dass lokal/regional erzeugte Lebensmittel geringere Umweltbelastungen -hinsichtlich Energieumsatz und CO2-Emission- verursachen als global erzeugte Lebensmittel, kann ebenso wie in bisher durchgeführten Untersuchungen zu Energiebilanzierungen von Prozessketten der Lebensmittel-bereitstellung (Fruchtsaft, Lammfleisch, Wein, Äpfel) nicht aufrechterhalten werden. Vielmehr verifizieren die Ergebnisse der hier durchgeführten qualitativen Analysen von Fallbeispielen die von SCHLICH 2004 geprägte TheorieThis work presents an energy evaluation of the supply chains of pork, beef and lamb. The execution of the analyses is oriented at a modified form of the CED (cumulated energy demand). For this purpose the ways of production and marketing of pork (Germany-Hessen and Hungary), beef (Germany-Hessen) an lamb (Germany-Hessen) from local supply chains are investigated. Data collection is carried out using standardized questionnaires. In addition to the mentioned analyses an evaluation of a global supply chain for beef from argentina is carried out as to compare local and global supply chains. Each supply chain will be subdivided to the modules transport, breeding-electrical energy, breeding-other energy, slaughtering/dissembling and distribution. The evaluation is achieved by allocation the energy turnover and carbon dioxyde emissions to the functional unit of 1 kg meat without bones. It is found that the energy turnover and CO2-emissions show a declining devolution related to an increasing size of businesses. Private consumer estimation expecting a lower energy turnover and environmental impact associated to meat of local origin can not be confirmed. In the same way former case studies on different food –juices, lamb, apples and wine- do, the work at hand demonstrates that the specific ecological impact does not depend on transport distance but rather on business size. It supports the theory o